Human B cell lymphoma is the most common form of non-Hodgkin's lymphoma in the United States. These neoplasms are of particular interest both clinically and scientifically due to their intrinsic involvement with the human immune system. This proposal seeks to develop effective methods for the in vitro study of human lymphoma cells displaying a B cell surface membrane phenotype. In these stdies, we will utilize fresh human biopsy-obtained lymphoma cells that have been purified by fluorescence-activitated cell sorting or lectin affinity. We have developed micro-assays that allow for the study of purified lymphoma cells for their response to B cell mitogens as well as their ability to undergo differentiation in vitro. Purified Interleukins, IL-1 and IL-2, which induce proliferation in normal lymphoid cells, will be evaluated for the capability of stimulating proliferation and differentiation in purified lymphoma cell populations. These and other soluble stimulatory factors for normal B lymphocytes will be evaluated for their potential use in liquid cell cultures and soft agar colony assays to develop more effective in vitro culture methods for B cell lymphoma cells. Non-neoplastic lymphoid cells present in lymphomatous lesions will be separated from the neoplastic cells and analyzed using monoclonal antibodies for their functional capabilities as well as their accessory cell potential for influencing the in vitro cultural characteristics of lymphoma cells. These studies should provide a contemporary immunologic approach to the in vitro characterization of human B cell lymphomas that will provide both clinically and biologically significant data.